Antineoplastic agents inhibit and combat the development of neoplasms, which are abnormal masses of tissue resulting from irregular proliferation of cells. One such antineoplastic agent is docetaxel, a taxane compound derived from the renewable needle biomass of yew plants. Docetaxel binds to free tubulin and promotes the assembly of microtubules, which reduces the availability of tubulin for, and thereby prevents, cell division. Simultaneously, docetaxel inhibits microtubule disassembly, causing apoptosis. See TAXOTERE® Prescribing Information.
Docetaxel is marketed as TAXOTERE®, which is FDA-approved for breast cancer, non-small cell lung cancer, hormone refractory prostate cancer, gastric adenocarcinoma, and squamous cell carcinoma of head and neck cancer. TAXOTERE® is available as an injection concentrate in single-dose vials containing 40 mg/mL docetaxel (on an anhydrous basis) and 1040 mg/mL polysorbate 80 (also known as TWEEN 80®). TAXOTERE® is provided as an injection concentrate and requires dilution to 10 mg/mL prior to use. Hence, a sterile, non-pyrogenic, single-dose diluent containing 13% ethanol in water for injection is supplied in a separate vial. After dilution, the required amount of docetaxel is then transferred from the 10 mg/mL initial diluted solution to an infusion bag or bottle of either 0.9% sodium chloride solution or 5% dextrose solution to produce a final dilution for infusion having a concentration of 0.3 to 0.74 mg/mL. The recommended therapy is six cycles of docetaxel given once every three weeks. See id.
The presence of polysorbate 80 in TAXOTERE®, however, most often results in serious side effects. Such reactions characterized by generalized rash/erythema, hypotension and/or bronchospasm, or very rarely fatal anaphylaxis, have been reported in patients. Hypersensitivity reactions require immediate discontinuation of the TAXOTERE® infusion and administration of appropriate therapy.
In order to reduce the side effects induced by polysorbate 80, patients are treated with dexamethasone for three days prior to therapy. Dexamethasone is a steroid that suppresses the immune response in patients, which can be especially detrimental in cancer patients under chemotherapy, whose immunity may already be compromised due to the destruction of healthy cells by the chemotherapeutic treatment. As a result, these patients can be susceptible to bacterial and fungal infections. Further, despite receiving the recommended 3-day dexamethasone premedication, patients still report hypersensitivity side effects from TAXOTERE®.
Due to these side effects, most of the patients stop TAXOTERE® therapy by the end of the second or third cycle, skip a dose, or continue further therapy at a reduced dose. Similarly, other solubilizing agents such as CREMOPHOR EL®, which is a polyethoxylated castor oil used in connection with the marketed paclitaxel product TAXOL®, induce similar allergic reactions requiring premedication with a steroid.
Therefore, a new formulation of docetaxel is needed to avoid these side effects, premedication requirements, and patient noncompliance issues associated with the currently marketed formulation of TAXOTERE®.